2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/199750We prove an identity [Eq. (1) below] among SU(2) 6j and 9j symbols that generalizes the Biedenharn-Elliott sum rule. We prove the result using diagrammatic techniques (briefly reviewed here), and then provide an algebraic proof. This identity is useful for studying meson-baryon scattering in which an extra isoscalar meson is produced.12 pages, REVTeX, 9 .eps figures, version accepted by J. Phys. AHigh Energy Physics - Phenomenologytext